Stock material or miscellaneous articles – Web or sheet containing structurally defined element or... – Adhesive outermost layer
Reexamination Certificate
1998-12-31
2001-05-08
Zirker, Daniel (Department: 1771)
Stock material or miscellaneous articles
Web or sheet containing structurally defined element or...
Adhesive outermost layer
C428S474400, C424S401000, C424S078030, C514S859000
Reexamination Certificate
active
06228487
ABSTRACT:
BACKGROUND OF THE INVENTION
This invention relates to the use of selected poly(vinyl acetamide) based adhesives in skin cleaning tapes to remove keratotic plugs as well as dirt and other matter from skin and skin pores.
Keratotic plugs are dead epidermal cells and oil which together with sebum, dirt and other skin debris can block and plug the pores of the skin. The formation of such plugs and skin build up are often conspicuous and can provide undesirable cosmetic effects. Additionally, if proper treatment is not given and these plugs and other build ups are not removed, various skin problems can arise.
Since keratotic plugs are formed deep in the skin, the use of traditional cleansers and detergents like soap, make-up removers and face masks are usually not effective in their removal. There have been some recent disclosures of skin cleaning compositions or methods to alleviate this problem. One method shown to remove keratotic plugs is found in U.S. Pat. No. 5,512,277 issued on Apr. 30, 1996 to T. Uemura et al., which discloses the use of synthetic cationic polymer compositions containing salt forming groups. In WO/32567 published on Sep. 12, 1997, a peel off type sheet pack is disclosed that comprises a multi-layer moisture-permeable support that includes a keratotic plug removing polymer material having an anionic, cationic or amphoteric salt-forming group. WO 98/05283 published on Feb. 12, 1998 discloses a sheet like pack with defined shape and further comprising a keratotic plug-removal polymeric compound having a salt forming group.
WO 98/42302 published Oct. 1, 1998 discloses a flexible substrate sheet for removing keratotic plugs comprising an adhesive composition containing an anionic, cationic, nonionic or amphoteric polymer such as polyvinyl pyrrolidone and poly(methyl vinyl ether/maleic anhydride) copolymer. WO 98/42304 published on Oct. 1, 1998 discloses a flexible non-occlusive substrate sheet for removing keratotic plugs containing an anionic or nonionic polymeric material such as the salts of poly(methyl vinyl ether/maleic anhydride) and polystyrene sulfonic acid and N-vinyl pyrrolidone.
Notwithstanding the above disclosures, there still is the need for additional skin cleaning and keratotic plug removing products, particularly one that is readily remoistenable and can be easily applied and effectively removed from the skin.
SUMMARY OF THE INVENTION
This invention relates to skin cleaning tapes for removing keratotic plugs and other debris and dirt found on the skin and in skin pores and comprising a poly(vinyl acetamide) polymer based adhesive composition applied to a substrate backing material. More particularly, this invention involves skin cleaning products comprising a polymer-based remoistenable adhesive composition wherein the polymer is a homopolymer of N-vinyl acetamide or an interpolymer prepared from N-vinyl acetamide and at least one other vinyl monomer.
This invention further involves a method for removing keratotic plugs from the skin using the selected remoistenable poly(vinyl acetamide) based adhesive as described herein.
DETAILED DESCRIPTION OF THE INVENTION
The present invention provides water-soluble, remoistenable, poly(vinyl acetamide) based adhesives for use as keratotic plug removers. The water soluble adhesives are coated or otherwise formed on a backing substrate which is then used to apply the adhesive composition to the skin to be treated.
The adhesive polymer used in this invention has good film forming properties, is easily remoistenable or re-wettable and provides good adhesion to the skin. More particularly, the adhesive polymer, poly(vinyl acetamide), i.e., PVAm is a homopolymer of N-vinyl acetamide (NVAm) or an interpolymer of NVAm and at least one other vinyl monomer. Preferably, the interpolymer will be prepared from at least about 10 percent by weight of NVAm, with the alance comprising vinyl monomer(s). Stated differently, the polymer will comprise from about 10 to 100 percent by weight of N-vinyl acetamide and from about 0 to 90 percent by weight of vinyl monomer. The preferred polymer is N-vinyl acetamide homopolymer.
The term “vinyl monomer”, as used herein, refers to vinyl monomers which are copolymerizable with NVAm. Particularly suitable vinyl monomers include, (a) C
1
-C
18
alkyl esters of acrylic acid; (b) C
1
-C
18
alkyl esters of methacrylic acid; (c) vinyl esters of the formula CH
2
═CH—OCOR where R is C
1
-C
18
; (d) alkyl substituted acrylamides and methacrylamides of the formula CH
2
═CR—CONR
1
R
2
where R is H or CH
3
, R
1
is H or C
1
-C
12
and R
2
is C
1
-C
18
; (e) hydroxy-substituted acrylates and methacrylates such as hydroxyethyl acrylate, hydroxypropyl acrylate, hydroxyethyl methacrylate, hydroxypropyl methacrylate and the like; (f) vinyl monomers containing an amine selected from the group consisting of secondary, tertiary and quaternary amines, such as n-vinyl imidazole, t-butylaminoethyl methacrylate (t-BAEM), dimethylaminoethyl methacrylate (DMAEMA), diethylaminoethyl methacrylate (DEAEMA), dimethylaminopropyl methacrylamide (DMAPMA) and the quarternized derivatives thereof such as methacrylatoethyltrimethyl ammonium chloride (MAPTAC), methacrylatoethyltrimethyl ammonium sulfate (MAETAS) and dimethyl diallyl ammonium chloride (DMDAAC); (g) acrylamide; and (h) non-alkyl substituted acrylamides such as diacetone acrylamide. Preferably, the vinyl comonomer is selected from the group consisting of methyl acrylate, methyl methacrylate, 2-hydroxyethyl acrylate, 2-hydroxyethyl methacrylate, 2-hydroxypropyl acrylate, 2-hydroxypropyl methacrylate, vinyl acetate, oligoethylene glycol monomethacrylate, and the vinyl monomers containing an amine selected from the group consisting of secondary, tertiary and quaternary amines.
The polymer, poly(vinyl acetamide), i.e., the homopolymer of N-vinyl acetamide or interpolymer of N-vinyl acetamide with vinyl monomer, as used in this invention, will generally have a weight average molecular weight of from about 30,000 to 2,000,000 and preferably from about 100,000 to 5,300,000.
Methods of making N-vinyl acetamide (NVAm) and the polymers thereof are known to those skilled in the art and are reported in Japanese publication numbers JP 08 81,428 published Mar. 26, 1996 and JP 08 134,029 published May 28, 1996. In the '428 publication N-(1-methoxyethyl) acetamide is prepared from dimethylacetal and acetamide in methanol and then thermally decomposed to obtain N-vinyl acetamide. Other methods are described in U.S. Pat. No. 4,942,259 issued Jul. 17, 1990 to G. Parris et al. where it is noted that percursors are formed and subsequently pyrolyzed or cracked to yield the desired vinyl amide. One such method is disclosed in U.S. Pat. No. 4,018,826 issued Apr. 19, 1977 to R. Gless et al. wherein acetaldehyde and acetamide are reacted to yield ethylidene-bis-acetamide which is thermally decomposed or cracked into vinyl acetamide. The '259 and '826 patents are hereby incorporated herein by reference.
A further embodiment of this invention is a blend of the poly(vinyl acetamide) polymer with one or more synthetic polymers or natural polymers. Examples of synthetic polymers which may be used include acrylate copolymers, acrylate/vinyl acetate copolymers, sodium polyacrylate, sodium polymethacrylate, polyvinylmethacrylate/methyl acrylate copolymers, octylacrylamide/acrylate/butylaminoethyl methacrylate copolymer, polyacrylamide, polyvinylacetate, vinylacetate/crotonic acid copolymer, vinyl acetate/crotonic acid/vinyl neodeconate copolymer, polyvinyl alcohol, polyvinyl formamide, and styrene/acrylate copolymers. Preferred synthetic polymers are polyvinyl formamide and copolymers thereof.
Natural polymers which may be blended with poly(vinyl acetamide) include starch, cellulose, guar gum and derivatives thereof. Useful derivatives of natural polymers include enzyme converted polymers, acid hydrolyzed polymers, oxidized polymers and polymers modified by etherification or esterification. Particularly useful modified polymers include hydroxyalkyl polymers pre
Cottrell Ian W.
Howard Doreen L.
Martino Gary T.
National Starch and Chemical Investment Holding Corporation
Roland Thomas F.
Zirker Daniel
LandOfFree
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